Normal air diffusion reduces tire pressure over time. The natural state of tires is under inflated. Accordingly, drivers must repeatedly act to maintain tire pressures or they will see reduced fuel economy, tire life and reduced vehicle braking and handling performance. Tire Pressure Monitoring Systems have been proposed to warn drivers when tire pressure is significantly low. Such systems, however, remain dependent upon the driver taking remedial action when warned to re-inflate a tire to recommended pressure. It is a desirable, therefore, to incorporate a self-inflating feature within a tire that will self-inflate the tire in order to compensate for any reduction in tire pressure over time without the need for driver intervention.
Self-inflating tire systems regulates the tire pressure. One problem is that the pressure of a tire changes with temperature. This may be due to the temperature increase due to the rise in ambient temperature, the operation of the tire, hysteresis losses, and as a result in the increase in vehicle speed. Generally, self-inflating tire systems allow inflation of a tire when the tire cavity pressure falls below a selected value. This selected value may not account for the increase in temperature. If the temperature rise is significant from an increase due to ambient temperature or vehicle speed, the system may not inflate the tire resulting in an underinflated tire. Thus it is desired to provide a temperature compensated pressure regulation system for air maintenance tires.